Recently I've created a simple "like" Pingdom app, that helps me monitor my deployed projects. Problems started, when I wanted to deploy this app, on a server where Redis is already working. When I've been starting resque workers, they've been throwing me same error:

rake aborted!
ERR unknown command 'blpop' 

I figured out, that my Redis instance was not up2date. however it was the most recent in repos. How to fix this? We need to add rwky/redis to our repos list:

sudo add-apt-repository ppa:rwky/redis
sudo apt-get update
sudo apt-get install redis-server

and thats all. After this, Resque works like a charm!